Solar primer

Mostly when we think of using the power of the sun in our homes we think: Expensive! Getting into solar power is not yet a cheap path, sunlight may be free but turning it into electricity isn’t. It’s the initial investment that stops most people, some keep going because the “buy back” (when the system has paid for itself) isn’t all that long (read:years) but mostly the sticker price to get started in a big way is a show stopper.

However, there are some ways to cut the cost. First there are “solar credits” from State and Federal governments and it is possible to lease a system rather than buy the whole thing yourself. The solar credits make a dent in the startup costs but it’s still expensive. Leasing is much cheaper but the leasing company gets a lot of the benefits we might have been hoping for. Things like selling power back to the utility.

Starting small

One way to cut the cost is to start out small, don’t think about trying to run your whole house, think about emergency power. A great emergency power system can be run on two solar panels and a big battery. This wont heat your home or run the washing machine but it will run some LED lights, a laptop and charge cell phones letting you stay connected to the rest of the world.

What you need to get started

A simple solar system needs three things to work effectively. Solar Panel(s) to make power, a Charge Controller to make that power useful, and a Battery to store the power. Solar power systems are like a mill pond for a saw mill. The pond fills slowly with water from a stream and then the water is let out in large amounts to run the mill. Working with solar power is about constantly storing power and then using it economically when you need it.

A slightly more advanced system would include an Inverter, a device that changes Direct Current from a battery into Alternating Current such as what is available from a common household outlet. This allows the use of regular appliances, vacuum cleaners, stereos, televisions, refrigerators etc, from battery power. So, lets talk about each of these components and what we might want to look for

Solar panels

In today’s market Solar panels come in three basic types. Monocrystalline, Polycrystalline and Amorphous. Monocrystaline panels are made of single wafers of crystal silicon and are the most efficient and expensive panels currently available. Polycrystalline panels are made of lost of pieces of silicon crystals and are cheaper than monocrystalline panels, but not as efficient. Amorphous panels, or thin film solar panels are the least expensive and the least efficient type of panel, but they offer the most flexibility of shape and installation. There are even amorphous solar panels that come on vinyl rolls that can be glued on any surface.

Charge controllers

All but the simplest systems use a charge controller. The charge controller takes in the power produced by the solar cells, which changes all the time based on available light, and uses it to consistently charge a battery or a bank of batteries. Because batteries are sensitive to things like over charging, a charge controller makes sure that doesn’t happen. Over charging a battery can ruin it. Good charge controllers also allow users to draw power from the system and will cut the power (or sound an alarm) when the batteries are getting low. The charge controller is the brains (or heart) of the solar system, good ones for small systems average about $100.

Batteries

Most small solar systems use 12 volt automotive batteries. While it’s possible to use any 12 volt battery most systems use “deep cycle” batteries because they are built to be deeply discharged and recharged many times. Most marine batteries are designed this way, and will last through many recharge cycles. However, a great deal of large systems use 6 volt deep cycle batteries for greater efficiency, they are a lot easier to move around and replace when they go bad. It is also easier to stack batteries in 6 volt increments to reach a desired system voltage. 5 batteries = 30 volts, 20 batteries = 120 volts. But for simplicity and ease of use lets stick to a 12 volt system.

Inverters

An Inverter can be a very handy piece of equipment, making regular appliances usable with just a battery. They can also be very inexpensive, as little as $15 dollars for one that plugs into the cigarette lighter socket to charge a cell phone. However, any appliance that is sensitive to it’s power, for example anything with a chip in it (just about everything these days) will not work safely with an inverter that doesn’t create AC power just like the power company does. If you want to run a refrigerator, a television, or a computer you will need a “true RMS” inverter that makes ac power that is true to what appliances expect. Unfortunately that ability makes an inverter more expensive, but they provide the safest, cleanest power you can get.

The Thunderbolt magnum 45 watt solar power kit $189

All together

It’s quite possible to get a solar power kit for less than $200, Harbor Freight has one going for $189. However, it doesn’t include a deep cycle battery or an inverter so we’d need to add those expenses on. Working on your own, a good setup can be put together for less than $600 pretty easily, with much better panels than the Amorphous ones in the Harbor freight kit.

It’s certainly easier to buy a kit when getting started, especially if you’re just looking for a short term emergency power source. Two things about the kits. First most cannot be expanded without a lot of trouble, things like finding compatible solar panels and a bigger charge controller that will work with those particular panels. Most solar systems are “matched” and you have to keep that in mind if you plan to expand later. Second, this is definitely a “you get what you pay for” situation. Good solar systems last 20 to 30 years, that would be the expectation when you pay for a house-sized system. Therefor, It’s a good idea to check the warranty on any kits you look at.

Of course, there really is nothing simpler than buying a kit to “get your feet wet” with a new technology.

Prentiss Gray is a writer and stay at home Dad with 27 years in the information systems and technology business. His favorite saying is “If you have to read the manual to use it, I don’t want one.” He can be reached via his website GrayResearch.net. More of his work can be seen on Speak Without Interruption or in his Patch blog.

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About Prentiss Gray

Prentiss Gray is a writer and stay at home Dad with 27 years in the information systems and technology business. After the death of his first wife, he decided to stay home and care for his three sons. During that time he discovered that his life long passion for technology had new worlds to explore. Lurking throughout his home, fascinating technologies were just waiting to be investigated.
Little by little, he began to crack the enigmas of washing machines and vacuums. He worked diligently to break the secret codes of wireless telephones and kitchen faucets and fought to understand why toasters and rice makers needed chips more advanced than those that flew on the Apollo moon missions.
The ongoing battle is endless, but he has developed a new attitude toward domestic technology. To clear out the complicated, to shun the needless effort necessary to deal with devices and products that do not serve their owners as much as confuse and frustrate them. In short, to seek out the domestic products that are have excellent quality, a reasonable price and are truly intuitive to use. His new battle cry is “If you have to read the manual to use it, I don’t want one.”

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